U.S. patent application number 12/907264 was filed with the patent office on 2012-04-19 for cylinder head cooling system.
This patent application is currently assigned to FORD GLOBAL TECHNOLOGIES, LLC. Invention is credited to Ted Beyer, John Christopher Riegger, Jody Michael Slike.
Application Number | 20120090565 12/907264 |
Document ID | / |
Family ID | 45895965 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120090565 |
Kind Code |
A1 |
Beyer; Ted ; et al. |
April 19, 2012 |
CYLINDER HEAD COOLING SYSTEM
Abstract
A cylinder head with an integrated exhaust manifold is provided,
the integrated exhaust manifold including an exhaust manifold
flange. In one example, the cylinder head includes a cooled flange
to control exhaust system heat. The cylinder head can improve
operation of an integrated cylinder head during at least some
operating conditions.
Inventors: |
Beyer; Ted; (Canton, MI)
; Slike; Jody Michael; (Farmington Hills, MI) ;
Riegger; John Christopher; (Ann Arbor, MI) |
Assignee: |
FORD GLOBAL TECHNOLOGIES,
LLC
Dearborn
MI
|
Family ID: |
45895965 |
Appl. No.: |
12/907264 |
Filed: |
October 19, 2010 |
Current U.S.
Class: |
123/41.82R |
Current CPC
Class: |
F01N 3/046 20130101;
Y02T 10/12 20130101; F02F 1/243 20130101; F01N 13/105 20130101;
Y02T 10/20 20130101; F02F 1/40 20130101 |
Class at
Publication: |
123/41.82R |
International
Class: |
F02F 1/40 20060101
F02F001/40 |
Claims
1. A cylinder head with an integrated exhaust manifold, the
integrated exhaust manifold including an exhaust manifold flange,
the cylinder head comprising: a coolant inlet in communication with
a cylinder head cooling system higher pressure passage; a coolant
outlet in communication with a cylinder head cooling system lower
pressure passage; and an exhaust flange coolant passage at least
partially traversing the exhaust manifold flange and in
communication with the coolant inlet and the coolant outlet.
2. The cylinder head of claim 1, wherein said exhaust flange
coolant passage includes at least one of an exhaust manifold flange
channel in the exhaust manifold flange and a channel in a second
flange included in a downstream component.
3. The cylinder head of claim 2, wherein the downstream component
is a turbocharger.
4. The cylinder head of claim 1, further comprising a sealing
gasket interposed by the exhaust manifold flange and a second
flange included in a downstream component.
5. The cylinder head of claim 4, wherein the sealing gasket
includes an inner seal and an outer seal coupled to the exhaust
manifold flange and the second flange and defining a boundary of
the exhaust flange coolant passage.
6. The cylinder head of claim 5, wherein the inner and outer seals
are coupled via connectors.
7. The cylinder head of claim 5, wherein the inner and outer seals
are metal embossments.
8. The cylinder head of claim 1, wherein the coolant inlet and
outlet are coupled to coolant passages extending into the cylinder
head.
9. The cylinder head of claim 1, further comprising a second
exhaust flange coolant passage at least partially traversing the
exhaust manifold flange including a second coolant inlet coupled to
a second higher pressure region of the cylinder head cooling system
and a second coolant outlet coupled to a second lower pressure
region of the cylinder head cooling system.
10. The cylinder head of claim 1, wherein the cylinder head cooling
system includes an upper and a lower cooling jacket and at least
one crossover coolant passages coupling the upper cooling jacket to
the lower cooling jacket.
11. A method for operation of a cylinder head cooling system in a
cylinder head of an engine, the cylinder head including an
integrated exhaust manifold, the method comprising: flowing coolant
into an exhaust flange coolant passage from a higher pressure
region of the cylinder head cooling system, the exhaust flange
coolant passage interposed between a exhaust manifold flange of an
exhaust outlet of an exhaust manifold integrated into the cylinder
head and a second flange included in a component downstream of the
integrated exhaust manifold; and flowing coolant from the exhaust
flange coolant passage into a lower pressure region of the cylinder
head cooling system.
12. The method of claim 11, further comprising flowing coolant into
the cylinder head cooling system integrated into the cylinder head
from at least one cylinder block coolant passage prior to flowing
coolant into the exhaust flange coolant passage, the cylinder head
cooling system including a plurality of integrated coolant passages
and the cylinder block coupled to the cylinder head to form at
least one combustion chamber.
13. The method of claim 11, wherein flowing coolant into the
cylinder head cooling system includes flowing coolant into an upper
cooling jacket included in the cylinder head cooling system from at
least one cylinder block coolant passage and flowing coolant into a
lower cooling jacket included in the cylinder head cooling system
from at least one cylinder block coolant passage.
14. The method of claim 13, further comprising flowing coolant
between the upper and lower cooling jackets via at least one
crossover coolant passage fluidly coupling the upper and lower
cooling jackets.
15. The method of claim 11, further comprising flowing coolant into
a second exhaust flange coolant passage from a higher pressure
region of the cylinder head cooling system.
16. The method of claim 15, further comprising flowing coolant from
the second exhaust flange coolant passage into a lower pressure
region of the cylinder head cooling system.
17. The method of claim 11, wherein the exhaust flange coolant
passage circumvents the exhaust outlet.
18. The method of claim 11, wherein cylinder head includes a
sealing gasket interposed by the exhaust manifold flange and the
second flange, the sealing gasket including an inner seal and an
outer seal coupled to the first flange and the second flange and
defining a boundary of the exhaust flange coolant passage.
19. The method of claim 11, further comprising selectively flowing
coolant into the exhaust flange coolant passage from a downstream
heat exchanger based on engine temperature, the downstream heat
exchanger configured to recover exhaust heat from an exhaust system
coupled to the exhaust manifold.
20. A cylinder head with an integrated exhaust manifold, the
integrated exhaust manifold including an exhaust manifold flange,
the cylinder head comprising: a coolant inlet in communication with
a higher pressure passage in a cylinder head cooling system, the
cylinder head cooling system configured to flow coolant through one
or more coolant passages; a coolant outlet in communication with a
cylinder head cooling system lower pressure passage; and an exhaust
flange coolant passage at least partially traversing the exhaust
manifold flange and in communication with the coolant inlet and the
coolant outlet, the exhaust flange cooling passage interposed
between the exhaust manifold flange and a flange of a downstream
component.
21. The cylinder head of claim 20, further comprising a sealing
gasket interposed by the exhaust manifold flange and a second
flange included in the downstream component, the sealing gasket
including an inner seal and an outer seal coupled to the exhaust
manifold flange and the second flange and defining a boundary of
the exhaust flange coolant passage.
22. The cylinder head of claim 20, wherein the integrated exhaust
manifold includes a plurality of exhaust runners each of the
exhaust runners having a valve guide entry point and a confluence
area, where at least one of a plurality of exhaust runners has a
cross-sectional area which contracts between the valve guide entry
point and the confluence area and at least one of the plurality of
exhaust runner has a cross-sectional area which expands in a curved
portion of the exhaust runner and which contracts at a straight
portion of the exhaust runner.
Description
BACKGROUND/SUMMARY
[0001] Exhaust manifolds for internal combustion engines may be
exposed to high thermal loads. Exhaust manifolds that are
integrated into cylinder heads may experience particularly high
thermal loading due to the heat transfer characteristics of the
integrated design. Thermal loading of an integrated exhaust
manifold and neighboring components can be reduced by incorporating
cooling jackets into the cylinder head. The cooling jackets can
reduce the thermal stresses on the cylinder head caused by heat
generated during engine operation. For example, a cylinder head
having an integrated exhaust manifold is disclosed in U.S. Pat. No.
7,367,294. An upper and a lower cooling jacket encompass a major
portion of the cylinder head to remove heat from the cylinder
head.
[0002] However, the inventors herein have recognized issues with
the above described approach. For example, the upper and lower
cooling jackets may not provide uniform cooling to the cylinder
head. Additionally, the flange at the outlet of the exhaust
manifold may experience higher temperatures than other portions of
the cylinder head because of flow patterns of the exhaust gasses
within the manifold. And, the upper and lower cooling jackets of
the prior approach appear to provide limited cooling of the flange
area. Furthermore, the cooling jacket of the prior approach may not
provide a sufficient amount of cooling to reduce the possibility of
thermal degradation on a turbocharger or components positioned
downstream of the exhaust manifold. Additionally, the cooling
jackets may not provide enough cooling to promote catalyst function
in an emission control system positioned downstream of the exhaust
manifold.
[0003] As such, various example systems and approaches are
described herein. In one example a cylinder head with an integrated
exhaust manifold is provided, the integrated exhaust manifold
including an exhaust manifold flange. The cylinder head including a
coolant inlet in communication with a cylinder head cooling system
higher pressure passage, a coolant outlet in communication with a
cylinder head cooling system lower pressure passage, and an exhaust
flange coolant passage at least partially traversing the exhaust
manifold flange and in communication with the coolant inlet and the
coolant outlet.
[0004] In this way, the temperature of the flange may be reduced
via the flange cooling subsystem so as to decrease thermal stresses
on the cylinder head. The flange cooling subsystem can decrease the
likelihood of thermal degradation of the cylinder head and
downstream components, such as a turbocharger, emission control
system, etc. Thus, performance of the engine, turbocharger, and
emission control system can be improved when the cylinder head
described above is utilized.
[0005] This Summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the Detailed Description. This Summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used to limit the scope of the claimed
subject matter. Furthermore, the claimed subject matter is not
limited to implementations that solve any or all disadvantages
noted in any part of this disclosure.
BRIEF DESCRIPTION OF THE FIGURES
[0006] FIG. 1 shows a schematic depiction of an internal combustion
engine.
[0007] FIG. 2 shows a schematic depiction of a cylinder head and
associated cooling system that may be included in the internal
combustion engine shown in FIG. 1.
[0008] FIG. 3 shows an illustration of an exemplary cylinder
head.
[0009] FIG. 4 shows a cross-sectional view of the cylinder head
shown in FIG. 3, the cylinder head including crossover coolant
passages.
[0010] FIG. 5 shows a side view of an exhaust manifold flange
included in the cylinder head shown in FIG. 3.
[0011] FIG. 6 shows another embodiment of the exhaust manifold
flange included in the cylinder head shown in FIG. 3.
[0012] FIG. 7 shows an exploded view of an exemplary exhaust
manifold flange, sealing gasket, and second flange.
[0013] FIG. 8 shows another embodiment of a sealing gasket.
[0014] FIG. 9 shows a side view of the second flange shown in FIG.
7.
[0015] FIG. 10 shows a cross-sectional view of the exhaust manifold
flange, sealing gasket, and second flange as well as the
corresponding coolant inlet, coolant outlet, and exhaust flange
coolant passage.
[0016] FIG. 11 shows a composite core for casting the cylinder head
shown in FIG. 3.
[0017] FIG. 12 shows a cross-sectional view of exhaust runners
included in the cylinder head shown in FIG. 3.
[0018] FIG. 13 shows an exhaust manifold port core included in the
composite core shown in FIG. 11.
[0019] FIG. 14 shows a cross-sectional view of entry conduits
included in the cylinder head shown in FIG. 3.
[0020] FIG. 15 shows a cross-sectional view a first outer exhaust
runner included in the cylinder head shown in FIG. 3.
[0021] FIG. 16 shows a cross-sectional view of another portion of
the first outer exhaust runner included in the cylinder head shown
in FIG. 3.
[0022] FIG. 17 shows a cross-sectional view a second inner exhaust
runner included in the cylinder head shown in FIG. 3.
[0023] FIG. 18 shows a method for operation of a cylinder head
cooling system in a cylinder head of an engine.
[0024] FIG. 19 shows a method for operation of a cylinder head
cooling system in a cylinder head of an engine.
DETAILED DESCRIPTION
[0025] A cylinder head with an integrated exhaust manifold is
described herein. The cylinder head including an exhaust flange
coolant passage in communication with a coolant inlet and a coolant
outlet. The coolant inlet and outlet may be in communication with a
higher and a lower pressure portion of a cylinder head cooling
system. The cylinder head cooling system may be configured to flow
coolant through passages in the cylinder head. In this way, cooling
may be provided to an exhaust flange which may experience higher
temperatures due to the flow characteristics within the integrated
exhaust manifold. Moreover, the exhaust coolant passage may also
provide cooling to neighboring components, such a turbocharger. In
this way, thermal stresses on the exhaust flange and components
downstream of the integrated exhaust manifold may be reduced. Thus,
the likelihood of thermal degradation of the exhaust flange,
cylinder block, or neighboring components, such as a turbocharger,
may be reduced thereby increasing the components longevity.
[0026] Referring to FIG. 1, internal combustion engine 10,
comprising a plurality of cylinders, one cylinder of which is shown
in FIG. 1, is controlled by electronic engine controller 12. Engine
10 includes combustion chamber 30 and cylinder walls 32 with piston
36 positioned therein and connected to crankshaft 40. Combustion
chamber 30 is shown communicating with intake manifold 44 and
exhaust manifold 48 via respective intake valve 52 and exhaust
valve 54. Each intake and exhaust valve may be operated by an
intake cam 51 and an exhaust cam 53. Alternatively, one or more of
the intake and exhaust valves may be operated by an
electromechanically controlled valve coil and armature assembly.
The position of intake cam 51 may be determined by intake cam
sensor 55. The position of exhaust cam 53 may be determined by
exhaust cam sensor 57.
[0027] Intake manifold 44 is also shown intermediate of intake
valve 52 and air intake zip tube 42. Fuel is delivered to fuel
injector 66 by a fuel system (not shown) including a fuel tank,
fuel pump, and fuel rail (not shown). The engine 10 of FIG. 1 is
configured such that the fuel is injected directly into the engine
cylinder, which is known to those skilled in the art as direct
injection. Fuel injector 66 is supplied operating current from
driver 68 which responds to controller 12. In addition, intake
manifold 44 is shown communicating with optional electronic
throttle 62 with throttle plate 64. In one example, a low pressure
direct injection system may be used, where fuel pressure can be
raised to approximately 20-30 bar. Alternatively, a high pressure,
dual stage, fuel system may be used to generate higher fuel
pressures.
[0028] Distributorless ignition system 88 provides an ignition
spark to combustion chamber 30 via spark plug 92 in response to
controller 12. Universal Exhaust Gas Oxygen (UEGO) sensor 126 is
shown coupled to exhaust manifold 48 upstream of catalytic
converter 70. Alternatively, a two-state exhaust gas oxygen sensor
may be substituted for UEGO sensor 126.
[0029] Converter 70 can include multiple catalyst bricks, in one
example. In another example, multiple emission control devices,
each with multiple bricks, can be used. Converter 70 can be a
three-way type catalyst in one example.
[0030] Controller 12 is shown in FIG. 1 as a conventional
microcomputer including: microprocessor unit 102, input/output
ports 104, read-only memory 106, random access memory 108, keep
alive memory 110, and a conventional data bus. Controller 12 is
shown receiving various signals from sensors coupled to engine 10,
in addition to those signals previously discussed, including:
engine coolant temperature (ECT) from temperature sensor 112
coupled to cooling sleeve 114; a position sensor 134 coupled to an
accelerator pedal 130 for sensing force applied by foot 132; a
measurement of engine manifold pressure (MAP) from pressure sensor
122 coupled to intake manifold 44; an engine position sensor from a
Hall effect sensor 118 sensing crankshaft 40 position; a
measurement of air mass entering the engine from sensor 120; and a
measurement of throttle position from sensor 58. Barometric
pressure may also be sensed (sensor not shown) for processing by
controller 12. In a preferred aspect of the present description,
engine position sensor 118 produces a predetermined number of
equally spaced pulses every revolution of the crankshaft from which
engine speed (RPM) can be determined.
[0031] In some embodiments, the engine may be coupled to an
electric motor/battery system in a hybrid vehicle. The hybrid
vehicle may have a parallel configuration, series configuration, or
variation or combinations thereof.
[0032] During operation, each cylinder within engine 10 typically
undergoes a four stroke cycle: the cycle includes the intake
stroke, compression stroke, expansion stroke, and exhaust stroke.
During the intake stroke, generally, the exhaust valve 54 closes
and intake valve 52 opens. Air is introduced into combustion
chamber 30 via intake manifold 44, and piston 36 moves to the
bottom of the cylinder so as to increase the volume within
combustion chamber 30. The position at which piston 36 is near the
bottom of the cylinder and at the end of its stroke (e.g. when
combustion chamber 30 is at its largest volume) is typically
referred to by those of skill in the art as bottom dead center
(BDC). During the compression stroke, intake valve 52 and exhaust
valve 54 are closed. Piston 36 moves toward the cylinder head so as
to compress the air within combustion chamber 30. The point at
which piston 36 is at the end of its stroke and closest to the
cylinder head (e.g. when combustion chamber 30 is at its smallest
volume) is typically referred to by those of skill in the art as
top dead center (TDC). In a process hereinafter referred to as
injection, fuel is introduced into the combustion chamber. In a
process hereinafter referred to as ignition, the injected fuel is
ignited by known ignition means such as spark plug 92, resulting in
combustion. During the expansion stroke, the expanding gases push
piston 36 back to BDC. Crankshaft 40 converts piston movement into
a rotational torque of the rotary shaft. Finally, during the
exhaust stroke, the exhaust valve 54 opens to release the combusted
air-fuel mixture to exhaust manifold 48 and the piston returns to
TDC. Note that the above is shown merely as an example, and that
intake and exhaust valve opening and/or closing timings may vary,
such as to provide positive or negative valve overlap, late intake
valve closing, or various other examples.
[0033] In one embodiment, the stop/start crank position sensor has
both zero speed and bi-directional capability. In some applications
a bi-directional Hall sensor may be used, in others the magnets may
be mounted to the target. Magnets may be placed on the target and
the "missing tooth gap" can potentially be eliminated if the sensor
is capable of detecting a change in signal amplitude (e.g., use a
stronger or weaker magnet to locate a specific position on the
wheel). Further, using a bi-dir Hall sensor or equivalent, the
engine position may be maintained through shut-down, but during
re-start alternative strategy may be used to assure that the engine
is rotating in a forward direction.
[0034] FIG. 2 shows a schematic depiction of a cylinder head
cooling system 200 for an engine. It will be appreciated that the
cooling system may be included in engine 10, shown in FIG. 1. The
cooling system may be configured to remove heat from the engine. As
discussed with greater detail herein, controller 12 may be
configured to regulate the amount of heat removed from the engine
via coolant circuit 250. In this way, the temperature of the engine
may be regulated allowing the combustion efficiency to be increased
as well as reducing thermal stress on the engine.
[0035] Cooling system 200 includes coolant circuit 250 traveling
through one or more cylinder block coolant passage(s) 251 in a
cylinder block 252. Water or another suitable coolant may be used
as the working fluid in the coolant circuit. The cylinder block may
include a portion of one or more combustion chambers. It will be
appreciated that the coolant circuit may travel adjacent to the
portions of the combustion chambers. In this way, excess heat
generated during engine operation may be transferred to the coolant
circuit. A cylinder head 253 may be coupled to the cylinder block
to form a cylinder assembly. When assembled, the cylinder assembly
may include a plurality of combustion chambers. Combustion chamber
30 shown in FIG. 1 may be included in the plurality of combustion
chambers.
[0036] The cylinder head cooling system further includes an upper
cooling jacket 254 and a lower cooling jacket 256. It will be
appreciated that the upper and lower cooling jackets are integrated
into the cylinder head. The upper cooling jacket includes a
plurality of coolant passages 258. Likewise, the lower cooling
jacket includes a plurality of coolant passages 260. As shown, the
upper cooling jacket includes a coolant inlet 262 and the lower
cooling jacket includes a coolant inlet 264. However, it will be
appreciated that the upper and/or lower cooling jackets may include
a plurality of inlets in other embodiments. For example, the upper
cooling jacket may include a single inlet and the lower cooling
jacket may include a plurality of inlets. It will be appreciated
that the inlets of the upper and lower cooling jackets may be
coupled to a common coolant passages in the cylinder block in some
embodiments. In this way, the upper and lower cooling jackets
receive coolant via their respective inlets from a common source
included in an engine block of an engine. However, in other
embodiments the inlets of the upper and lower cooling jackets may
be coupled to separate coolant passages in the cylinder block.
[0037] A first set of crossover coolant passages 266 may fluidly
couple the upper cooling jacket 254 to the lower cooling jacket
256. Similarly, a second set of crossover coolant passages 268 may
fluidly couple the upper cooling jacket to the lower cooling
jacket.
[0038] Each crossover coolant passage included in the first set of
crossover coolant passages may include a restriction 270. Likewise,
each crossover coolant passage included in the second set of
crossover coolant passages may include a restriction 271. Various
characteristics (e.g., size, shape, etc.) of the restrictions may
be tuned during construction of cylinder head 253. Therefore, the
restrictions 270 included in the first set of crossover coolant
passages may be different in size, shape, etc., than the
restrictions 271 included in the second set of crossover coolant
passages. In this way, the cylinder head may be tuned for a variety
of engines, thereby increasing the cylinder head's applicability.
Although two crossover coolant passages are depicted in both the
first and second sets of crossover coolant passages, the number of
crossover coolant passages included in the first set and second
sets of crossover coolant passages may be altered in other
embodiments.
[0039] The crossover coolant passages allow coolant to travel
between the cooling jackets at various points between the inlets
and the outlets of both the upper and lower cooling jackets. In
this way, the coolant may travel in a complex flow pattern where
coolant moves between the upper and lower jackets, in the middle of
the jacket and at various other locations within the jacket. The
mixed flow pattern reduces the temperature variability within the
cylinder head during engine operation as well as increases the
amount of heat energy that may be removed from the cylinder head,
thereby improving engine performance.
[0040] The cylinder head cooling system may be coupled to at least
one coolant passage 272 included in an exhaust manifold flange 273.
The exhaust manifold flange is included in an exhaust manifold 48.
The coolant passage 272 includes a coolant inlet 274 and a coolant
outlet 275. The coolant inlet may be coupled to a higher pressure
coolant passage in the cylinder head cooling system and the coolant
outlet may be coupled to a lower pressure coolant passage in the
cylinder head coolant system. It will be appreciated that the
higher pressure coolant passage may be included in the upper or
lower cooling jacket. Likewise, the lower pressure coolant passage
may be included in the upper or lower cooling jacket. In one
particular example, the higher pressure coolant passage is included
in the lower cooling jacket and the lower pressure coolant passage
is included in the upper cooling jacket. In this way, coolant may
be circulated around the flange, enabling heat to be removed from
the flange, using an existing cooling system in the vehicle.
Therefore, it will be appreciated that the manufacturing cost may
be reduced when compared to other systems which may use independent
cooling system to provide cooling to an exhaust system. Moreover,
thermal stresses on the cylinder head flange as well as neighboring
components may be reduced, thereby increasing the components
longevity. The exhaust manifold coolant passage is discussed in
greater detail herein with regard to FIGS. 3 and 5-10.
[0041] The upper cooling jacket includes an outlet 276. Outlet 276
may include a restriction 277. Additionally, the lower cooling
jacket includes an outlet 278. It will be appreciated that in other
embodiments outlet 278 may also include a restriction. The outlets
from both the upper and lower cooling jackets may combine and be in
fluidic communication. The coolant circuit may then travel through
one or more radiator coolant passage(s) 280 included in a radiator
282. The radiator enables heat to be transferred from the coolant
circuit to the surrounding air. In this way, heat may be removed
from the coolant circuit.
[0042] A pump 284 may also be included in the coolant circuit. A
thermostat 286 may be positioned at the outlet 276 of the upper
cooling jacket. A thermostat 288 may also be positioned at the
inlet of the one or more coolant passage(s) 251 of the cylinder
block 252. Additional thermostats may be positioned at other
locations within the coolant circuit in other embodiments, such as
at the inlet or outlet of the one or more coolant passage(s) in the
radiator, the inlet or outlet of the lower cooling jacket, the
inlet of the upper cooling jacket, etc. The thermostats may be used
to regulate the amount of fluid flowing through the coolant circuit
based on the temperature. In some examples, the thermostats may be
controlled via controller 12. However in other examples, the
thermostats may be passively operated.
[0043] It will be appreciated that controller 12 may regulate the
amount of pressure head provided by pump 284 to adjust the
flow-rate of the coolant through the circuit and therefore the
amount of heat removed from the engine. Furthermore, in some
examples controller 12 may be configured to dynamically adjust the
amount of coolant flow through the upper cooling jacket via
thermostat 286. Specifically, the flow-rate of the coolant through
the upper cooling jacket may be decreased when the engine
temperature is below a threshold value. In this way, the duration
of engine warm-up during a cold start may be decreased, thereby
increasing combustion efficiency and decreasing emissions. It will
be appreciated that the systems and components in FIG. 2 are
schematically depicted and not meant to depict the relative
location of the components.
[0044] FIG. 3 shows a perspective view of an example cylinder head
253. The cylinder head may be configured to attach to a cylinder
block (not shown) which defines one or more combustion chambers
having a piston reciprocally moving therein. The cylinder head may
be cast out of a suitable material such as aluminum. Other
components of an assembled cylinder head have been omitted. The
omitted components include a camshafts, camshaft covers, intake and
exhaust valves, spark plugs, etc.
[0045] As shown, cylinder head 253 includes four perimeter walls.
The walls include a first and a second side wall, 302 and 304
respectively. The four perimeter walls may further include a front
end wall 306 and a rear end wall 308.
[0046] A bottom wall 312 may be configured to couple to the
cylinder head (not shown) thereby forming the engine combustion
chambers, as previously discussed. The cylinder head may further
include a de-gas port 314 including a valve configured to remove
gas from the upper cooling jacket. In this way, the amount of gas
in both the upper and lower cooling jacket may be reduced. The
de-gas port is positioned in an area adjoining an upper surface of
the upper cooling jacket. In some examples, the de-gas port may be
positioned at a crest (e.g., substantially highest vertical point)
in the upper cooling jacket. However in other examples, the de-gas
port may be positioned in another suitable location. The de-gas
port may decrease the amount of gas (e.g., air and/or water vapor)
in both the upper and lower cooling jacket, thereby increasing
operating efficiency of the upper and lower cooling jackets.
[0047] Cylinder head 253 further includes exhaust manifold 48 to
which a plurality of exhaust runners are coupled. The exhaust
runners are illustrated and discussed in more detail with regard to
FIGS. 12-17. The exhaust runners may be coupled to the exhaust
valves for each combustion chamber. In this way, the exhaust
manifold and exhaust runners may be integrated into the cylinder
head casting. The integrated exhaust runners have a number of
benefits, such as reducing the number of parts within the engine
thereby reducing cost throughout the engine's development cycle.
Furthermore, inventory and assembly cost may also be reduced when
an integrated exhaust manifold is utilized.
[0048] The cylinder head further includes exhaust manifold flange
273 surrounding the exhaust manifold 48. The flange includes bolt
bosses 310 or other suitable attachment apparatuses configured to
attach to a downstream exhaust component, such as an exhaust
conduit or an inlet of a turbine included in a turbocharger. In
this way, the turbocharger may be mounted directly to the cylinder
head reducing losses within the engine. The turbocharger may
include an exhaust driven turbine coupled to a compressor via a
drive shaft. The compressor may be configured to increase the
pressure in the intake manifold.
[0049] Additionally, the cylinder head further includes coolant
inlet 274 in communication with a higher pressure passage in
cylinder head cooling system 200, shown in FIG. 2, and a coolant
outlet 275 in communication with a lower pressure passage in the
cylinder head cooling system. As shown, the higher and lower
pressure passages extend into the cylinder head. The higher and
lower pressure passages are shown in FIG. 10. It will be
appreciated that the higher and/or lower pressure passages in the
cylinder head cooling system may be in either the upper or lower
cooling jacket. As shown, the exhaust manifold flange further
includes an exhaust manifold flange channel 315 traversing the
exhaust manifold flange. The flange channel may be cast or may be
milled after the cylinder head is cast. As depicted, the exhaust
manifold flange channel extends around the entire exhaust manifold
flange. In other words, the exhaust manifold flange channel
circumvents exhaust outlet 316. However, in other embodiments the
flange channel may partially traverse the exhaust manifold flange.
The flange channel may define a boundary of an exhaust flange
coolant passage at least partially traversing the exhaust manifold
flange. The exhaust flange cooling passage may be coupled to the
coolant inlet 274 and the coolant outlet 275. In this way, coolant
may be circulated through the exhaust flange coolant passage. The
exhaust flange coolant passage may be interposed between the
exhaust manifold flange and a flange of a downstream component,
such as a turbocharger, exhaust passage, emission control device,
etc., discussed in greater detail herein. Cutting plane 320 defines
the cross-section shown in FIG. 4. Cutting plane 322 defines the
cross-section shown in FIG. 10. Cutting plane 324 defines the
cross-section shown in FIG. 12. Cutting plane 326 defines the
cross-section shown in FIG. 14. Cutting plane 328 defines the
cross-section in shown FIG. 15. Cutting plane 330 defines the
cross-section shown in FIG. 16. Cutting plane 332 defines the
cross-section shown in FIG. 17.
[0050] FIG. 4 shows a cut-away view of cylinder head 253 shown in
FIG. 3. A first crossover coolant passage 410 is shown. The first
crossover coolant passage 410 may be included in the first set of
crossover coolant passages 266 shown in FIG. 2. Continuing with
FIG. 4, arrow 412 denotes the general path of the fluid traveling
through the first crossover coolant passage from the lower cooling
jacket to the upper cooling jacket. As shown, the coolant travels
in a substantially vertical direction through a vertically aligned
passage, relative to vertical piston motion of pistons in the
cylinder. It will be appreciated that the width of the first
crossover coolant passage may be altered during construction via
machining. In this way, the crossover coolant passage may be tuned
to a desired specification.
[0051] The first set of crossover coolant passages may be radially
aligned with two or more cylinders included in the engine. It will
be appreciated that the alignment may be about a single line of
symmetry. The first set of crossover coolant passages may be also
spaced away from the inlet and/or exhaust ports in the engine.
Positioning the first set of crossover coolant passages in
alignment with two or more cylinder and away from the inlet and/or
exhaust ports enables the structural integrity of the cylinder head
to be increased when compared to crossover coolant passages that
may be positioned adjacent to inlet or exhaust ports which may
decrease the thickness of the metal surrounding the exhaust valve,
thereby increasing the likelihood of exhaust or intake valve
degradation or failure. Furthermore, a larger diameter flow channel
may be utilized when the crossover flow channels are aligned in
this way when compared to crossover coolant channels that are
positioned adjacent to intake or exhaust valves.
[0052] A second crossover coolant passage 414 is also shown. The
second crossover coolant passage 414 may be included in the second
set of crossover coolant passages 268 shown in FIG. 2. The second
crossover coolant passage is adjacent to a periphery of the
cylinder head and spaced away from the exhaust outlet 316.
Therefore, it will be appreciated that the second set of crossover
coolant passages may be adjacent to a periphery of the cylinder
head and spaced away from the exhaust manifold. Arrow 416 denotes
the general path of the fluid traveling through the first crossover
coolant passage from the lower cooling jacket to the upper cooling
jacket. As shows cup 418 both directs and restricts flow through
the first crossover coolant passage. The flow pattern of the
coolant through the second set of crossover coolant passages
follows an arc. When a cup is used to direct the flow of coolant
through the second crossover coolant passage, this enables the
construction process (e.g., machining) of the cylinder head to be
simplified.
[0053] FIG. 5 shows a side view of the exhaust manifold flange 273
and exhaust outlet 316 of exhaust manifold 48, shown in FIG. 3.
Similar parts are labeled accordingly.
[0054] FIG. 6 shows a side view of an alternate embodiment of
exhaust manifold flange 273. As shown, the exhaust manifold flange
includes a first coolant inlet 602 and a first coolant outlet 604.
As previously discussed, the first coolant inlet and outlet are
coupled to a higher pressure passage in the cylinder head cooling
system and a lower pressure passage in the cylinder head cooling
system. A first flange channel 606 extends between the first
coolant inlet and the first coolant outlet. Additionally, the
exhaust manifold flange includes a second coolant inlet 608 and a
second coolant outlet 610. A second flange channel 612 extends
between the second coolant inlet and the second coolant outlet.
Further, in some embodiments channels may also extend between the
first and second coolant inlets and the first and second coolant
outlets. The first and second coolant channels may define a
boundary of an exhaust flange coolant passage, discussed in greater
detail herein with regard to FIGS. 7-10.
[0055] FIG. 7 shows an exploded view of exhaust manifold flange
273, a sealing gasket 702, and a second flange 704. When assembled
bolts 706 or other suitable attachment apparatuses may couple the
aforementioned components. Therefore, when assembled the sealing
gasket is interposed between the exhaust manifold flange and the
second flange.
[0056] Sealing gasket 702 may include an inner seal 708 and an
outer seal 710. The inner and outer seals define a boundary of the
exhaust flange cooling passage. Thus, the inner and outer seal
enable coolant to be circulated around the exhaust manifold flange
and substantially prevent coolant from leaking into the exhaust
stream or the exterior of the cylinder head.
[0057] In some examples, the inner and outer seals may be
multi-layered metal embossments. Therefore, the seals may be
raised. In other words, the seals may have a greater lateral
thickness than other portions of the sealing gasket. However, other
suitable seals may be utilized on other examples. For example, in
addition to or as an alternative rubber seals may be utilized.
Though metal seals may be preferred due to their ability to
withstand high temperatures than rubber seals. The inner seal may
be in face sharing contact with both the exhaust manifold flange as
well as flange 704. Additionally, the outer seal may be in face
sharing contact with both the exhaust manifold flange as well as
flange 704.
[0058] The sealing gasket further includes transfer openings 712.
As shown, the transfer openings are aligned with the coolant inlet
274 and the coolant outlet 275. However, other alignments are
possible. In this way, coolant may be circulated around the exhaust
manifold flange as well as flange 704. It will be appreciated that
this may not only reduce the temperature of the exhaust manifold
flange, decreasing the likelihood of thermal degradation of the
cylinder head but also reduces the temperature of neighboring
components, such as a turbocharger, thereby reducing the likelihood
of thermal degradation of the neighboring component.
[0059] However in other embodiments, sealing gasket 702 may not
include transfer openings 712 and the inner and outer seals (708
and 710) may only be in face sharing contact with the exhaust
manifold flange. Thus, coolant may be circulated around the exhaust
manifold flange. However, heat may be transferred from flange 704
to the coolant via conduction through the sealing gasket 702.
[0060] FIG. 8 shows an alternate embodiment of sealing gasket 702.
As shown an opening 802 extends around the sealing gasket. In other
words, the opening circumvents the inner edge 804 of the sealing
gasket. As shown, connectors 806 span opening 802. It will be
appreciated that when connectors are utilized the relative position
of the inner seal to the outer seal may be substantially fixed
reducing the likelihood of improper assembly, such as improper
placement (e.g., spacing) of the inner and outer seal. In some
examples, the lateral distance of one or more of the connectors may
not be equal. It will be appreciated that when the connectors are
positioned in this way a coolant flow pattern may be generated that
reduces losses within the exhaust flange coolant passage. In this
way, the efficiency of the exhaust manifold cooling system may be
increased when compared to a cooling system having connectors
positioned with equivalent lateral distances.
[0061] FIG. 9 shows flange 704. Flange may be included in a
downstream component, such as a turbocharger or an exhaust conduit.
Flange 704 includes a channel 902. Channel 902 may be milled or
cast. However, in other embodiments channel 902 may not be included
in flange 704. Channel 902 may define a boundary of the exhaust
flange coolant passage. Channel 902 allows a greater amount of
coolant to be circulated around flange 704 increasing the amount of
heat that may be removed from the flange and associated
component.
[0062] FIG. 10 shows a cross-sectional view of exhaust manifold
flange 273, sealing gasket 702, and flange 704. The general
direction of exhaust gas flow through the exhaust outlet 316 is
denoted via arrow 1002. Coolant in the cylinder head cooling system
flows from a higher pressure passage 1004 into the exhaust manifold
coolant passage 1006 via coolant inlet 274. As previously
discussed, the inner seal 708 and the outer seal 710 define a
boundary of the exhaust flange coolant passage 1006. Furthermore,
exhaust manifold flange channel 315 and channel 902 may also define
a boundary of the exhaust flange coolant passage 1006. However in
other examples, flange channel 315 may not be included in the
exhaust manifold flange and/or channel 902 may not be included in
flange 704. It will be appreciated that coolant may travel through
transfer openings 712, shown in FIG. 7. Thus, during operation of
the cylinder head cooling system coolant flows around a portion of
the exhaust manifold flange 273 as well as flange 704. The coolant
may exit the exhaust flange coolant passage 1006 via coolant outlet
275 (shown in FIGS. 3, 4, 5, and 7) coupled to a lower pressure
passage 1008 in the cylinder head cooling system. In this way, heat
may be removed from both the exhaust manifold flange 273 as well as
flange 704, reducing the thermal stresses on the cylinder head as
well as downstream components such as a turbocharger.
[0063] FIG. 11 shows a composite core 1100 including an upper core
1102, a lower core 1104, and an exhaust manifold port core 1106.
These casting cores are positioned as shown and would be placed
together into an exterior mold during a casting process. Metal
poured into the mold may then take the shape of the molds,
hardening and forming cylinder head 253. Such a casting process is
well known in the art.
[0064] As shown, vertically aligned protrusions 1150 included in
both the upper and lower core may define the first set of crossover
coolant passages 266. It will be appreciated that the crossover
coolant passages may be vertically orientated relative to piston
motion. The laterally aligned extensions 1152 in both the upper and
lower core may define the second set of crossover coolant passages
268. It will be appreciated that horizontally aligned extension
1103 may define outlet 276 of the upper cooling jacket including
restriction 277. As shown, the casting includes protrusions 1154
and 1156 forming coolant passages extending from the flange into
the cylinder head. The ends of protrusions form coolant inlet 274
and coolant outlet 275. However, it will be appreciated that in
other examples the coolant passages may be milled after the
cylinder head is cast. The upper and lower cooling jackets define a
plurality of coolant passages, as previously discussed.
Furthermore, the exhaust manifold port core defines an exhaust
manifold including a plurality of exhaust runner fluidly coupled to
an exhaust outlet.
[0065] FIG. 12 shows a cross-sectional view of exhaust manifold 48
included in the cylinder head 253 shown in FIG. 3. Exhaust outlet
316, included in the exhaust manifold, is coupled to a first inner
exhaust runner 1210 for a cylinder positioned between two other
cylinders. The first inner exhaust runner 1210 includes a first
entry conduit 1212 and a second entry conduit 1214 meeting at a
confluence area 1216. The first and second entry conduits include a
first and a second valve guide entry point (1410 and 1412), shown
in FIG. 14. It will be appreciated that the valve guide entry
points may be configured to each receive a portion of an exhaust
valve. Exhaust outlet 316 is also coupled to a second inner exhaust
runner 1218. The second inner exhaust runner 1218 includes a first
entry conduit 1220 and a second entry conduit 1222 meeting at a
confluence area 1224. The first and second entry conduit include a
first and second valve guide entry point (1414 and 1416), shown in
FIG. 14. The exhaust runners receive exhaust gases from a cylinder
during engine operation. The valve guide entry points allow exhaust
valves to be positioned in the cylinder head such that the exhaust
valves can limit gas flow from the cylinder to the exhaust runners.
Therefore, each inner exhaust runner includes two entry conduits
coupled to two exhaust valves. However, in other examples, the
first and second inner exhaust runner may each include a single
valve guide entry point. Therefore, in such an example, the first
inner exhaust runner and the second inner exhaust runner each
include a single entry conduit.
[0066] It will be appreciated that both of the inner exhaust
runners may be coupled to cylinders positioned between two other
cylinders. The first and second inner exhaust runners may converge
at a confluence area 1226 for mixing exhaust gases from the inner
cylinders. As shown, the first and second inner exhaust runners may
be directed in a substantially straight path to the exhaust outlet
316.
[0067] The exhaust manifold further includes a first outer exhaust
runner 1228 and a second outer exhaust runner 1230 coupled to
exhaust outlet 316. The first and second outer exhaust runners are
coupled to cylinders positioned at each the end of a cylinder bank.
In other words, the first and second outer exhaust runners are
coupled to the outermost cylinders in a cylinder bank with an
inline configuration. The first outer exhaust runner includes a
first entry conduit 1232 and a second entry conduit 1234 meeting at
a confluence area 1236. The first and second entry conduits (1232
and 1234) include a first valve guide entry port and a second valve
guide entry port (1418 and 1420) shown in FIG. 14. Likewise, the
second outer exhaust runner includes a first entry conduit 1238 and
a second entry conduit 1240 meeting at a confluence area 1242. The
first and second entry conduits (1238 and 1240) include a first
valve guide entry point and a second valve guide entry point (1422
and 1424) shown in FIG. 14.
[0068] The second outer exhaust runner 1230 and the second inner
exhaust runner 1218 may converge at a confluence area 1244 for
mixing exhaust gases from the inner and outer cylinders. Likewise,
the first outer exhaust runner 1228 the first inner exhaust runner
1210 may converge at a confluence area 1246 for mixing exhaust
gases from the inner and outer cylinders.
[0069] The first outer exhaust runner has a lead-in angle 1248.
Lead-in angle 1248 may be defined as the intersection of a line
parallel to a straight portion of outer-wall 1250 of the first
outer exhaust runner 1228 and a plane spanning exhaust outlet 316.
The outer-wall of the first outer exhaust runners may be a
vertically aligned wall adjacent to side wall 302, shown in FIG. 3.
Due to the symmetry of the exhaust manifold, it will be appreciated
that the second outer exhaust runner has an identical lead-in
angle.
[0070] It has been found unexpectedly that when the outer exhaust
runners have a lead-in angle between 15 and 17 degrees flow
separation in the exhaust gases during engine operation may be
reduced, thereby reducing losses in the exhaust manifold.
Specifically, a lead-in angle of 15.5 degrees may be utilized to
decrease flow separation in the exhaust manifold. A lead-in angle
within this range may also reduce impingement of the exhaust gases
on the exhaust manifold walls. Furthermore, a lead-in angle within
this range may also reduce the amount of cross-talk between the
exhaust valves. For example, reaction waves generated during
exhaust valve operation in the outer exhaust runners may be
propagated downstream of the exhaust manifold as opposed to in the
other exhaust runners. Therefore, exhaust valves having a lead-in
angle between 15 and 17 degrees are utilized. In this way, engine
operation may be improved via the reduction of cross-talk between
the exhaust valves.
[0071] FIG. 13 shows the exhaust manifold port core of the exhaust
manifold shown in FIG. 12. Although a core print is shown, it will
be appreciated that exhaust gases may travel through the passages
defined by the exhaust manifold port core. Therefore, corresponding
parts are labeled accordingly.
[0072] Line 1318 indicates a cutting plane of a location of the
beginning of a region of the exhaust manifold port core of a first
outer exhaust runner 1228 where the cross-sectional area of first
outer exhaust runner 1228 is measured from. Line 1320 indicates a
cutting plane of an example location on the curved portion of first
outer exhaust runner 1228 where the cross-sectional area of the
curved portion of first outer exhaust runner 1228 can be measured.
Lines 1326 and 1328 indicate cutting planes of example locations on
the straight portion of first outer exhaust runner 1228 where the
cross-sectional area of the straight portion of first outer exhaust
runner 1228 can be measured. At line 1318, first outer exhaust
runner 1228 has a first cross-sectional area. At line 1320, first
outer exhaust runner 1228 has a second cross-sectional area. At
lines 1326 and 1328, first outer exhaust runner 1228 has a third
cross-sectional area. The first outer exhaust runner 1228 expands
from the first cross-sectional area to the second cross-sectional
area and contracts from the second cross-sectional area to the
third cross-sectional area. Similarly, line 1322 of the second
outer exhaust runner 1230 indicates a cutting plane of a location
of the beginning of a region of the exhaust manifold port core
where the cross-sectional of the exhaust runner is measured from.
Line 1324 indicates a cutting plane of an example location on the
curved portion of the second outer exhaust runner 1230 where the
cross-sectional area of the curved portion of second outer exhaust
runner 1230 can be measured.
[0073] Line 1310 indicates a cutting plane of an example location
of the beginning of a region of the exhaust manifold port core of
the first inner exhaust runner 1210 where the cross-sectional area
of inner exhaust runner 1210 is measured from. Line 1312 indicates
a cutting plane of an example location of the first inner exhaust
runner 1210 where the cross-sectional area of inner exhaust runner
1210 is measured. At line 1310, the first inner exhaust runner 1210
has a first cross-sectional area. At line 1312, first inner exhaust
runner 1210 has a second cross-sectional area. The first
cross-sectional area is greater than the second cross-sectional
area. Similarly, line 1314 indicates a cutting plane of an example
location of the beginning of a region of the exhaust manifold port
core of second inner exhaust runner 1218 where the cross-sectional
area of inner exhaust runner 1218 is measured from. Line 1316
indicates a cutting plane of an example location of second inner
exhaust runner 1218 where the cross-sectional area of inner exhaust
runner 1218 is measured. Line 1330 indicates a cutting plane of
another example location of second inner exhaust runner 1218 where
the cross-sectional area of the second inner exhaust runner 1218 is
measured.
[0074] FIG. 14 shows a cross-sectional view of the first valve
guide entry point 1410 and the second valve guide entry point 1412
and corresponding entry conduits (1212 and 1214) for the first
inner exhaust runner 1210. Additionally, FIG. 14 shows the first
valve guide entry point 1414 and the second valve guide entry point
1416 and corresponding entry conduits (1220 and 1222) for the
second inner exhaust runner 1218. FIG. 14 further shows the first
valve guide entry point 1418 and the second valve guide entry point
1420 and corresponding entry conduits (1232 and 1234) for the first
outer exhaust runner 1228. FIG. 14 also shows the first valve guide
entry point 1422 and the second valve guide entry point 1424 and
corresponding entry conduits (1238 and 1240) for the second outer
exhaust runner 1430. The cross-sectional area of the first inner
exhaust runner between each of the two valve guide entry points
(1410 and 1412) may be substantially 716 mm.sup.2. For reference,
the leading boundary, line 1310, and the trailing boundary, line
1312, of the sections of the first inner exhaust runner 1210 are
shown in FIG. 13. It will be appreciated that the cross-sectional
area is measured via a plane spanning the exhaust runner and
perpendicular to a line 1450 tangent to the central axis of the
exhaust runner. Likewise, the cross-sectional area of the second
inner exhaust runner 1218 between each of the two valve guide entry
points (1414 and 1416) may be substantially 716 mm.sup.2. For
reference, the leading boundary, line 1314, and the trailing
boundary, line 1316, of the sections of the second inner exhaust
runner 1218 are shown in FIG. 13. The cross-sectional area of the
first outer exhaust runner between each of the two valve guide
entry points (1418 and 1420) may be substantially 716 mm.sup.2. For
reference, the leading boundary, line 1318, has a cross-sectional
area that may be substantially 716 mm.sup.2 are shown in FIG. 13
Likewise, the cross-sectional area of the second outer exhaust
runner 1230 between each of the two valve guide entry points (1422
and 1424) may be substantially 716 mm.sup.2. For reference, the
leading boundary, line 1322, has a cross-sectional area that may be
substantially 716 mm.sup.2 are shown in FIG. 13.
[0075] FIG. 15 shows a cross-sectional view of the first outer
exhaust runner 1228 in a curved portion of the exhaust runner
downstream of the valve guide entry points (1418 and 1420) and
upstream of confluence area 1246 in the direction of exhaust flow
from the cylinder, shown in FIG. 12. As previously discussed, the
cross-sectional area of the first outer exhaust runner begins at a
first area and expands as the exhaust runner curves and contracts
as the exhaust runner reaches a confluence point where exhaust
gases from one cylinder mix with exhaust gases of another cylinder.
The first outer exhaust runner 1228 starts at the first area of
substantially 716 mm.sup.2 at a location downstream of the valve
guide entry points (1418 and 1420) in a direction of exhaust
flow.
[0076] The cross-sectional area of the first outer exhaust runner
in the curved portion of the exhaust runner shown in FIG. 15 may be
716 mm.sup.2. For reference, the leading boundary, line 1320, and
trailing boundary, line 1326, of the curved portion of the first
outer exhaust runner is shown in FIG. 13. As previously discussed
the cross-sectional area may be measured via a plane spanning the
exhaust runner and perpendicular to a line tangent to the central
axis of the exhaust runner. Due to the symmetry within the exhaust
manifold the second outer exhaust runner is similar in geometry and
size to the first outer exhaust runner.
[0077] FIG. 16 shows a cross-sectional view of the first outer
exhaust runner 1228 in a straight portion of the exhaust runner
downstream of the valve guide entry points (1418 and 1420) in the
direction of exhaust flow and upstream of confluence area 1246. For
reference, the leading boundary, line 1326, and trailing boundary,
line 1328, of the straight portion of the first outer exhaust
runner is shown in FIG. 13.
[0078] The cross-sectional area of the straight portion of the
first outer exhaust runner may be less than the cross-sectional
area of the curved portion of the first outer exhaust runner.
Therefore, the cross-sectional area along the length of the first
outer exhaust runner contracts in a straight portion of the exhaust
runner. In particular, the cross-sectional area of the straight
portion of the exhaust runner shown may be 651 mm.sup.2. Due to the
symmetry within the exhaust manifold, the second outer exhaust
runner is similar in geometry and size to the first outer exhaust
runner. Therefore, the second outer exhaust runner may also
experience an expansion and downstream contraction.
[0079] It has been unexpectedly found that the expansion and
subsequent contraction in the first and second outer exhaust
runners may reduce flow separation of the exhaust gases within the
outer exhaust runners, thereby decreasing losses within the exhaust
manifold. When losses within the exhaust manifold are reduced the
energy delivered to the turbine of the turbocharger positioned
downstream of the exhaust manifold is increased thereby increasing
the engine's efficiency and potential power output.
[0080] FIG. 17 shows a cross-sectional view of the second inner
exhaust runner 1218 in a portion of the exhaust runner downstream
of the valve guide entry points (1414 and 1416) in the direction of
exhaust flow and upstream of confluence area 1244. The
cross-sectional area of this portion may be less than the
cross-sectional area of the exhaust runner downstream of the valve
guide entry points in the direction of exhaust flow. Specifically,
the cross-sectional area may be 660 mm.sup.2. For reference the
leading boundary, line 1316, and trailing boundary, line 1330, of
the portion of the second inner exhaust runner discussed above is
shown in FIG. 13. In this way, the cross-sectional area of the
second inner exhaust runner along the length of the exhaust runner
contracts. Due to the symmetry of the exhaust manifold it will be
appreciated that the first inner exhaust runner is similar in
geometry and size to the second inner exhaust runner.
[0081] The contraction in the first and second inner exhaust
runners concentrates the exhaust gases in the center of the exhaust
outlet 316, decreasing impingement of exhaust gases on the walls of
the exhaust outlet 316. As such, the exhaust manifold losses can be
decreased. Therefore, the energy delivered to the turbine via the
exhaust gases may be increased when compared to other exhaust
manifolds that do not have a contraction. In this way, the
efficiency of the turbocharger and therefore the engine may be
increased.
[0082] The cylinder head shown in FIGS. 2-17 provides for a
cylinder head with an integrated exhaust manifold, the integrated
exhaust manifold including an exhaust manifold flange. The cylinder
head including a coolant inlet in communication with a cylinder
head cooling system higher pressure passage, a coolant outlet in
communication with a cylinder head cooling system lower pressure
passage, and an exhaust flange coolant passage at least partially
traversing the exhaust manifold flange and in communication with
the coolant inlet and the coolant outlet. Further in some examples
said exhaust flange coolant passage includes at least one of an
exhaust manifold flange channel in the exhaust manifold flange and
a channel in a second flange included in a downstream component. In
some examples, the downstream component may be a turbocharger. The
cylinder head may further include a sealing gasket interposed by
the exhaust manifold flange and a second flange included in a
downstream component. The sealing gasket may include an inner seal
and an outer seal coupled to the exhaust manifold flange and the
second flange and defining a boundary of the exhaust flange coolant
passage. Additionally the inner and outer seals may be coupled via
connectors. The inner and outer seals may be metal embossments. The
coolant inlet and outlet may be coupled to coolant passages
extending into the cylinder head. The cylinder head may further
include a second exhaust flange coolant passage at least partially
traversing the exhaust manifold flange including a second coolant
inlet coupled to a second higher pressure region of the cylinder
head cooling system and a second coolant outlet coupled to a second
lower pressure region of the cylinder head cooling system. In some
examples the cylinder head cooling system includes an upper and a
lower cooling jacket and at least one crossover coolant passages
coupling the upper cooling jacket to the lower cooling jacket. In
some example the integrated exhaust manifold includes a plurality
of exhaust runners each of the exhaust runners having a valve guide
entry point and a confluence area, where at least one of a
plurality of exhaust runners has a cross-sectional area which
contracts between the valve guide entry point and the confluence
area and at least one of the plurality of exhaust runner has a
cross-sectional area which expands in a curved portion of the
exhaust runner and which contracts at a straight portion of the
exhaust runner.
[0083] FIG. 18 shows a method 1800 for operation of a cylinder head
cooling system in a cylinder head of an engine, the cylinder head
having an integrated exhaust manifold. Method 1800 may be carried
out by the systems and components described above. However, method
1800 may be implemented by other suitable systems and components in
other embodiments.
[0084] First at 1802 the method includes flowing coolant into a
cylinder head cooling system integrated into the cylinder head from
at least one cylinder block coolant passage. As previously
discussed, the cylinder head cooling system may include a plurality
of integrated coolant passages and the cylinder block coupled to
the cylinder head to form at least one combustion chamber.
[0085] In some examples flowing coolant into a cylinder head
cooling system from at least one cylinder head coolant passage may
include flowing coolant into an upper cooling jacket included in a
cylinder head cooling system from at least one cylinder block
coolant passage at 1804. Further in some examples, flowing coolant
into a cylinder head cooling system from at least one cylinder head
coolant passage may include flowing coolant into a lower cooling
jacket included in the cylinder head cooling system from at least
one cylinder block coolant passage at 1806.
[0086] Next at 1808, the method includes flowing coolant into an
exhaust flange coolant passage from a higher pressure region of the
cylinder head cooling system. As previously discussed, the exhaust
flange coolant passage may be interposed between an exhaust
manifold flange of an exhaust outlet of an exhaust manifold
integrated into the cylinder head and a second flange included in a
component downstream of the integrated exhaust manifold. In some
examples, the flange coolant passage may circumvent the exhaust
outlet. However in other examples, the flange coolant passage may
only partially traverse the exhaust manifold flange. As previously
discussed, the cylinder head may include a sealing gasket
interposed by the exhaust manifold flange and the second flange,
the sealing gasket including an inner seal and an outer seal
coupled to the first flange and the second flange and defining a
boundary of the flange coolant passage.
[0087] Next at 1810, the method may include flowing coolant into a
second exhaust flange coolant passage from a higher pressure region
of the cylinder head cooling system. However in other examples,
step 1810 may not be included in method 1800. Next at 1812, the
method includes flowing coolant from the exhaust flange coolant
passage into a lower pressure region of the cylinder head cooling
system.
[0088] At 1814, the method may include flowing coolant from the
second exhaust flange coolant passage into a lower pressure region
of the cylinder head cooling system. However in other examples,
step 1814 may not be included in method 1800. Next at 1816, flowing
coolant between the upper and lower cooling jackets via at least
one crossover coolant passage fluidly coupling the upper and lower
cooling jackets. It will be appreciated that in some embodiments
step 1816 may be implemented after step 1802 and before step
1806.
[0089] Next at 1818, the method includes flowing coolant from the
cylinder head cooling system to a coolant conduit coupled to a
radiator. In some examples, flowing coolant from the cylinder head
cooling system to a coolant conduit coupled to a radiator may
include at 1820 flowing coolant from an outlet of the lower cooling
jacket into a coolant conduit coupled to a radiator. Still further
in some examples flowing coolant from the cylinder head cooling
system to a coolant conduit coupled to a radiator may include at
1822 flowing coolant from an outlet of the upper cooling jacket
into a coolant conduit coupled to the radiator.
[0090] FIG. 19 shows a method 1900 for operation of a cylinder head
cooling system in a cylinder head of an engine. Method 1900 may be
carried out by the systems and components described above. However,
method 1900 may be implemented by other suitable systems and
components in other embodiments.
[0091] First at 1902, the method includes determining if the engine
is below a threshold temperature. The threshold temperature may be
calculated based on the material properties of the type of fuel
used in the engine, the type of emission control system coupled to
the engine, etc. If it is determined that the engine is not below a
threshold temperature (NO at 1902), method 1900 proceeds to 1904
where method 1800 is implemented. After 1904 the method ends.
However if it is determined that the engine is below a threshold
temperature (YES at 1902), the method advances to 1906 where the
method includes flowing coolant into an exhaust flange coolant
passage from a downstream heat exchanger. In this way, coolant may
be selectively flowed into the exhaust flange coolant passage from
a downstream heat exchanger based on engine temperature. The
downstream heat exchanger may be configured to recover exhaust heat
from an exhaust system coupled to the exhaust manifold. As such,
exhaust gas heat may be transferred from the exhaust gases to the
exhaust flange during and engine cold start to reduce the amount of
time to heat exhaust system components. The method may further
include after step 1906 in some examples substantially inhibiting
coolant flow from the cylinder block to the cylinder head. After
1906 the method ends. In this way, heat may be transferred to the
exhaust flange coolant passage during a cold start, increasing the
temperature of the exhaust system and thereby improving operation
of an emission control system downstream of the exhaust manifold
flange.
[0092] The systems and methods described herein enables the flange
included in an exhaust manifold, decreasing the likelihood of
thermal degradation of the exhaust manifold (e.g., flange), thereby
increasing the longevity of the exhaust manifold. Furthermore, it
will be appreciated that the exhaust flange coolant passage may be
constructed via the modification of many existing parts in a
cylinder head, decreasing size and cost of the cylinder head.
[0093] It will be appreciated that the configurations and/or
approaches described herein are exemplary in nature, and that these
specific embodiments or examples are not to be considered in a
limiting sense, because numerous variations are possible. The
subject matter of the present disclosure includes all novel and
nonobvious combinations and subcombinations of the various
features, functions, acts, and/or properties disclosed herein, as
well as any and all equivalents thereof.
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